Technical Field
The present invention relates to an image forming apparatus using an intermediate transfer belt.
Description of the Related Art
As an electrophotographic image forming apparatus, an image forming apparatus using an intermediate transferer is known. In the apparatus, a toner image formed on a photoconductor is first transferred onto an intermediate transferer, and then the toner image thereon is second transferred onto a transfer material. As the intermediate transferer, an intermediate transfer belt which is an endless belt is widely used.
In the image forming apparatus using an intermediate transferer, a toner which is not transferred onto the transfer material after the second transfer (residual toner after the second transfer) remains on the intermediate transfer belt. Therefore, a cleaning process removing the residual toner after the second transfer on the intermediate transfer belt before a following image is transferred thereonto is needed. For the cleaning process, blade cleaning methods using a cleaning blade formed of an elastic body such as a urethane rubber as a cleaning member are widely used. The cleaning blade is often installed at an acute angle relative to a travel direction of the intermediate transfer belt to improve its cleanability. Namely, the cleaning blade is often contacted to almost all width nearly perpendicular to the travel direction of the intermediate transfer belt while a free end of the cleaning blade contacting thereto faces upstream of the travel direction of the intermediate transfer belt. Such a method of cleaning the intermediate transfer belt is known.
An intermediate transfer belt formed by extrusion using a thermoplastic resin is cleaned by the above method as well. However, foreign matters are inserted in between the intermediate transfer belt and the edge of the cleaning blade.
The foreign matters are peculiarly are inserted in therebetween when the intermediate transfer belt is formed by extrusion using a thermoplastic resin. A skin layer formed on the surface of the intermediate transfer belt is scraped off by friction with the cleaning blade.